I've been in a lot of office pools over the years, some of them as big as 300 entries! Depending on how the pool is scored, it really comes down to Sweet 16, Elite 8, and Final Four games. These random upsets here and there don't really affect your bracket as long as your Final 4 teams remain. In some ways, it's less stressful if you're eliminated from winning a pool early, but if there's a chance to win money during the Final Four and you have no emotional attachment to the teams, it really can be a fun experience.